Strand orientation alignment in strand coating systems and methods

ABSTRACT

A strand coating system and method including drawing (710) a strand having major and minor dimensions past an adhesive dispensing nozzle, orienting (720) at least a portion of the strand so that the major dimension of the strand is substantially parallel to a direction in which adhesive is dispensed from the adhesive dispensing nozzle as the portion of the strand is drawn past the adhesive dispensing nozzle, and applying (730) adhesive to the strand as the strand is drawn past the adhesive dispensing nozzle.

CROSS REFERENCE TO RELATED APPLICATION

The present application is related to co-pending U.S. application No.09/758,702 filed on 11 Jan. 2001 entitled “Variable Spacing StrandCoating System And Modular Guide Roller Therefor” and to co-pending U.S.application No. 09/621,721 filed on 24, Jul. 2000 entitled “VariableSpacing Strand Coating System And Method”, assigned commonly with thepresent application and incorporated by reference herein.

FIELD OF THE DISCLOSURE

The disclosure relates generally to strand coating systems and methods,and more particularly to systems, sub-systems and methods for applyingcoatings to elongated strands having asymmetric cross sections, forexample, the application of vacillating adhesive filaments to elasticstrands having rectangular cross sections prior to adherence on asubstrate or between substrates, methods and systems therefor.

BACKGROUND OF THE DISCLOSURE

It is known generally to apply adhesive coatings to elongated strands.U.S. Pat. No. 6,077,375 entitled “Elastic Strand Coating Process”, forexample, discloses the application of vacillating adhesive filamentsdispensed from a nozzle onto elastic and other strands, some of whichare adhered onto a substrate or in some applications between adjacentsubstrates. In one exemplary application disclosed in U.S. Pat. No.6,077,375, a vacillating meltblown adhesive filament is captured on anelastic strand drawn past a nozzle from which the adhesive is dispensed.And in some applications in U.S. Pat. No. 6,077,375, the vacillatingadhesive filament is substantially entirely captured by the strand as ittends to wrap around the strand, coating the sides thereof substantiallyuniformly along the strand axis prior to adherence of the strand onto asubstrate in the manufacture of bodily fluid absorbing personal hygienicarticles.

It is also known to align elongated strands with a nozzle from which anadhesive filament is dispensed by drawing the strands over a groovedguide roller located upstream of the nozzle, as disclosed, for example,to the reference U.S. application No. 09/758,702 entitled “VariableSpacing Strand Coating System And Modular Guide Roller Therefor” and thereferenced U.S. application No. 09/621,721 entitled “Variable SpacingStrand Coating System And Method”. See also, the ITW DYNATEC INTEGRAstrand coating system.

The known exemplary strand coating systems and technologies discussedabove work well for applying adhesive materials to elastic strandshaving substantially uniform cross-sections, for example, square orcircular cross-sectional shapes. In some applications, however, theadhesive or other substance is applied to a strand having an asymmetriccross sectional shape, for example, a substantially rectangularsectional shape. These applications include the application of adhesivesonto natural rubber or elastic tape used in the manufacture of bodilyfluid absorbent hygienic articles. In applications where thecross-sectional shape of the elastic strand is rectangular orasymmetric, the known prior art adhesive coating systems tend to applythe adhesive material on the elastic strand unevenly. Specifically, theadhesive tends to adhere more on one side of the strand, for example,the wider edge thereof, than to other sides of the strand. Moreover, insome applications, the strand tends to flip from side to side as it isdrawn along the strand guide resulting in the application of theadhesive material to different sides of the strand. In someapplications, for example, those where the strand is bonded betweensubstrates, among others, the uneven application of adhesive material tothe strand compromises the integrity of the bond, since some portions ofthe strand may be devoid of adhesive.

The objects, aspects, features and advantages of the present disclosurewill become more fully apparent upon careful consideration of thefollowing Detailed Description thereof and the accompanying Drawings,which may be disproportionate for ease of understanding, wherein likestructure and steps are referenced generally by corresponding numeralsand indicators.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an adhesive material applied to one side of anexemplary strand having a substantially rectangular cross-sectionalshape.

FIG. 2 is a first view of an exemplary strand coating system.

FIG. 3 is a second view of the exemplary strand coating system.

FIG. 4 is a third view of the exemplary strand coating system.

FIG. 5 illustrates a strand oriented relative to a fluid dispensingnozzle.

FIG. 6 illustrates an exemplary strand having a substantiallyrectangular cross-sectional shape disposed between substrates.

FIG. 7 is an exemplary process diagram.

FIG. 8 is an exemplary strand axial orientation aligning member mountingbracket.

DETAILED DESCRIPTION OF THE DISCLOSURE

The disclosure is drawn generally to systems, sub-systems and methodsfor controlling the orientation of at least a portion of a strand aboutits axial dimension as the strand portion is drawn past a fluid orliquid dispensing nozzle, for example, in an adhesive dispensing systemthat applies a hot melt adhesive filament from an adhesive dispensingorifice of an adhesive dispensing device or apparatus onto an elasticstrand used in the manufacture of personal hygienic articles. Accordingto the disclosure, these and other adhesive dispensing systems generallyinclude a strand axial orientation aligning member.

FIGS. 2-4 illustrate an exemplary strand coating system 200 includinggenerally an adhesive dispensing device 210 having one or more adhesivedispensing orifices. In the exemplary embodiment of FIG. 4, the adhesivedispensing device 210 includes first and second orifices 211 and 212that each dispense an adhesive fiber or filament onto a correspondingstrand. In one exemplary strand coating application, the adhesivefilaments vacillate predominately transversely to the path of thecorresponding strands. These and related filament producing apparatusesare known generally and discussed more fully, for example, in U.S. Pat.No. 6,200,635 entitled “Omega Spray Pattern And Method”, in U.S. Pat.No. 5,902,540 entitled “Meltblowing Method And Apparatus”, and in U.S.Pat. No. 5,902,298 entitled “Improved Meltblowing System”, among otherreferences in the prior art. However, the inventions are not limited toany particular type of fluid or liquid dispensing apparatus or system.

In an alternative embodiment, the adhesive dispensing system or deviceis a spiral nozzle that dispenses a generally helical filament or fiber.In other embodiments, other filament dispensing devices may be usedalternatively. Although the exemplary applications concern theapplication of adhesive fibers or filaments onto elastic strands, thedisclosure has much wider applicability, including the applicationfilaments onto other strand types, which are not necessarily elastic,and to the application of atomized liquids onto the strands, forexample, the application of atomized lubricants onto fibers, among otherapplications, as will be appreciated in view of the discussion below.

In the FIGS. 2-4, the exemplary adhesive dispensing device 210 ismounted on a module 220 that controls the supply of adhesive and air orother gas to the adhesive dispensing device 210. The module may beoperated pneumatically or electrically. The module 220 or similar devicemay also be used to control the supply of adhesive and/or air to spiralnozzles and to other adhesive dispensing devices, for example, to spiralnozzles. The exemplary module 220 is mounted on a head 240, whichprovides a metered supply of adhesive or other material and air to theadhesive dispensing device via the module. In other embodiments, theadhesive and any required gas may be provided to the nozzle by someother structure, for example, the adhesive dispensing orifices may bepart of an integrated assembly rather than the modular assembly of theexemplary embodiment.

The exemplary system of FIGS. 2-4 also includes an optional strand guidemember 230 for guiding aligning the strand along a drawing path relativeto the adhesive dispensing nozzle. In FIGS. 2 and 4, the exemplarystrand guide 230 is a strand guide roller having first and secondgrooves 232 and 234 for guiding corresponding strands 233 and 235relative to corresponding orifices of the adhesive dispensing device210. In other embodiments, other types of strand guides may be used, forexample, non-rotating strand guides. The strand guide is generallylocated upstream of the adhesive dispensing device and functionsgenerally to align the path of one more strands with the adhesivedispensing device. In some embodiments, the strand guide is notrequired.

In embodiments where a strand guide is employed and in applicationssubject to vibration, the strand guide is preferably coupled to theadhesive dispensing device so that the strand guide and adhesivedispensing device vibrate in unison. In the exemplary embodiment ofFIGS. 2-4, the stand guide roller 230 is adjustably mounted on the head240 by first and second adjustably positionable arms 236 and 238, whichpermit adjusting the spacing between the strands and the adhesivedispensing device and also permit adjusting the upstream location of thestrand guide roller. In other embodiments, the strand guide roller isnot necessarily coupled to the adhesive dispensing device, and thestrand guide position is not necessarily adjustable.

According to another aspect of the disclosure, at least one strand axialorientation aligning member is disposed proximate each orifice of thefluid or liquid dispensing device. In applications where an adhesive orother material is applied to the strand, the strand axial orientationaligning member is preferably disposed on an upstream side of adhesivedispensing device. In the exemplary embodiment of FIGS. 2-4, a strandaxial orientation aligning member 252 is positioned between each orificeof the fluid or liquid dispensing device and the strand guide roller230. In one embodiment, the strand axial orientation aligning ispositioned so that it is generally aligned, for example, on one side orthe other, with a corresponding orifice of the adhesive dispensingdevice. Generally, the strand is drawn so that is passes along thestrand axial orientation aligning member and over or under acorresponding orifice of the fluid or liquid dispensing device.

In the exemplary embodiment of FIG. 4, first and second strand axialorientation aligning members 250 and 252 and aligned generally withcorresponding orifices 212 and 214, respectively, of the adhesivedispensing device 210. In FIGS. 2-4, the exemplary strand axialorientation aligning members are mounted on a plate 254 fastened to themodule 220. The exemplary strand axial orientation aligning member is apin shaped member having an axis extending substantially transversely toa direction in which the strand is drawn past the adhesive dispensingdevice. In the alternative embodiment of FIG. 8, an alternative mountingplate 854 is configured so that first and second strand axialorientation aligning members 850 and 852 are aligned generally withcorresponding orifices 812 and 814, respectively, of the adhesivedispensing device 810 on an opposite side of the orifices 812 and 814.The alternative mounting plate of FIG. 8 is suitable for applicationswhere the strand is drawn in the direction of arrow 802, thuspositioning the strand axial orientation aligning members on an upstreamside of the orifices. The mounting plate 854 of FIG. 8 is distinguishedfrom the mounting plate 254 of FIG. 2 by an opening 855 that permits theorifices to dispense material without obstruction. In other embodiments,however, the strand axial orientation aligning members are not mountedor otherwise coupled to the adhesive dispensing device, for example, thestrand axial orientation aligning members may be mounted or supported bysome other isolated structure.

Generally, the strand axial orientation aligning member controls anorientation of at least a portion of the strand about its axialdimension as the strand portion is drawn past the adhesive dispensingnozzle. The strand axial orientation aligning member also preciselyaligns the strand with the orifice of the adhesive dispensing device. Inthe exemplary strand coating application, the strand axial orientationaligning member controls the orientation of the strand portion bypreventing twisting of the strand portion about its axial dimension atleast in a neighborhood of the adhesive dispensing nozzle. Thus thestrand axial orientation aligning member fixes the orientation of thestrand at least as the strand is drawn past the orifice of the adhesivedispensing nozzle.

In FIG. 3, the exemplary strand axial orientation aligning memberincludes first and second flanges 256 and 257 separated by a guidingportion 258. The strand 235 is retained between the first and secondflanges, thereby essentially fixing the distance between the strand andthe adhesive dispensing device 210. Structure other than the strandaxial orientation aligning member may be used alternatively to fix thedistance between the strand and the device 210 in embodiments where itis desirable to control or fix the spacing between the strand and theorifice.

In one embodiment, the strand has at least one relatively flat side orsurface along its axial dimension. In FIG. 5, for example, the exemplarystrand 510 has a substantially rectangular cross-sectional shape withmajor and minor axes or dimensions. The major dimension has flat sides511 and 513 along the axial direction of the strand. The orientation ofthe strand portion about its axial dimension is controlled by engagingthe substantially flat side of the strand with the strand axialorientation aligning member as the strand is drawn past the fluid orliquid dispensing device. In FIG. 5, the strand is oriented so that themajor axis of the cross-sectional dimension of the strand issubstantially parallel to the direction in which a vacillating adhesivefilament 520 is dispensed from a dispensing device 530 by a similarlyaligned strand axial orientation aligning member, which is not visiblein FIG. 5. The strand orientation illustrated in FIG. 5 is desirable insome strand coating applications, for example, those where the strand iscoated with a vacillating filament of fiber as illustrated in FIG. 5 toensure that the strand is coated on both sides 512 and 514 along themajor dimension or axis. In other embodiments, the strand may beoriented at different angles by orientating the angle of the guidingsurface of the strand axial orientation aligning member. For example,the major dimension of the strand cross-section may be madesubstantially transverse to the direction of the adhesive flow with atransversely disposed strand axial orientation aligning member. Inanother embodiment, the strand may be oriented at other angles.

In FIG. 1, where the major dimension of the rectangular strand 110 isaligned transversely to the path of the filament 120, the strand tendsto be coated on only one side thereof. The filament in FIG. 1 may be asubstantially planar vacillating filament or a helical filament. Also,in many stand coating applications, the strand tends to twist back andforth about its axial dimension as it is drawn past the adhesivedispensing device, for example, where the strand is subject tovibration. If the twisting strand is symmetrical about its axialdimension the twisting thereof may not have an adverse affect on theapplication of adhesive onto the strand. However, in applications wherethe twisting strand has a rectangular cross-section, the twisting strandtends to be coated on only one side thereof facing the orifice when themajor dimension of the strand is transverse to the path of the adhesivefilament. Thus a twisting strand having a rectangular cross-sectionaldimension will not be uniformly coated with adhesive along its axialdimension.

While not an issue for some applications, partial or incompleteapplications of adhesive along the axial dimension of the strand isproblematic for others. FIG. 6 illustrates an application where anadhesive coated strand 610 is bonded between first and second substrates620 and 630, for example, in the manufacture of personal hygienicarticles. Thus in applications like those illustrated in FIG. 6, it isdesirable to uniformly coat the strand on both sides 612 and 614 alongits major axis to ensure complete bonding along the axial dimension ofthe strand. Orienting the strand as illustrated in FIG. 5, with a strandaxial orientation aligning member will ensure uniform coating of thestrand on opposite sides of the major dimension along the axialdimension of the strand.

In the exemplary embodiment, a tangential force is applied to the strandas the strand is drawn over the strand axial orientation aligning memberby guiding the strand in a groove of the strand guide roller that is notaligned with the adhesive dispensing orifice, as illustrated best inFIG. 4. Particularly, one of the grooves 232 or 234 of the strand guideroller guides the strand along a path that is misaligned with theorifices 212 and 214 of the adhesive dispensing device. A correspondingone of the strand axial orientation aligning members 250 or 252 changesthe direction of the strand 233 and 235 in alignment with the orifices212 and 214. The tangential force biases the strand against the strandaxial orientation aligning member as the strand is drawn past theadhesive dispensing device. The biasing force enables the strand axialorientation aligning member to maintain the desired orientation of thestrand about its axial dimension at least in a neighborhood of theadhesive dispensing device. In an alternative embodiment, notillustrated, the strand may be captured between two strand axialorientation aligning members. In the alternative embodiment, it may beunnecessary to tangentially bias the strand about the strand axialorientation aligning member with a misaligned strand guide.

In the exemplary strand coating process diagram 700 of FIG. 7, at block710, a strand having an asymmetric cross-sectional shape, for example, arectangular shape with major and minor dimensions, is drawn past anadhesive dispensing nozzle. In some embodiments, the strand is alignedalong a drawing path relative to the adhesive dispensing nozzle beforeorienting the portion of the strand, for example with a strand nozzleroller.

At block 720, an orientation of at least a portion of the strand ismaintained as the portion of the strand is drawn past the adhesivedispensing nozzle. In the exemplary adhesive dispensing application, themajor dimension of the strand is aligned and fixed substantiallyparallel to a direction in which adhesive is dispensed from the adhesivedispensing nozzle. In some applications, orientation includes preventingtwisting of the portion of the strand oriented to maintain itsorientation relative to the adhesive dispensing nozzle as the portion ofthe strand is drawn past the adhesive dispensing nozzle.

In FIG. 7, at block 730, a liquid or fluid, for example, a hot meltadhesive is applied to the strand as the strand is drawn past theadhesive dispensing nozzle. In some embodiments, applying adhesive tothe strand as the strand is drawn past the adhesive dispensing nozzleincludes capturing a vacillating filament dispensed from the adhesivedispensing nozzle on opposite sides of the strand substantially parallelto the direction in which adhesive is dispensed from the adhesivedispensing nozzle. In other embodiments, however, the adhesive filamentmay not be vacillating, for example, it may be a spiral filament or achaotic filament. Also, in some embodiments, it may not be desirable tocapture the filament on both sides of the strand, for example, in someapplications it is desirable capture the filament on only one side ofthe strand, which is having its major dimension oriented transversely tothe general direction of the filament.

While the foregoing written description of the disclosure enables one ofordinary skill to make and use what are considered presently to be thebest modes thereof and evidences the rightful possession thereof, thoseof ordinary skill will understand and appreciate the existence ofvariations, combinations, and equivalents of the specific exemplaryembodiments herein. The inventions are therefore to be limited not bythe exemplary embodiments herein, but by all embodiments within thescope and spirit of the appended claims.

1. A strand coating apparatus, comprising: a module; a fluid dispensingdevice having a fluid dispensing orifice, the fluid dispensing devicecoupled to an end of the module; a plate coupled to a bottom of themodule and extending beyond the end of the module to which the fluiddispensing device is coupled, the plate having an opening aligned withthe fluid dispensing orifice. a strand orienting pin protruding from aside of the plate opposite from a side of the plate on which the fluiddispensing device is located.
 2. The apparatus of claim 1, a strandguide member coupled to the module; the strand orientating pin locatedsubstantially between the strand guide member and the fluid dispensingorifice, the strand orienting pin offset relative to a path between thefluid dispensing orifice and the strand guide member.
 3. The apparatusof claim 2, the strand guide member includes a strand guide groove, thestrand orienting pin offset relative to a path between the fluiddispensing orifice and the strand guide groove.
 4. The apparatus ofclaim 3, the fluid dispensing device is an adhesive dispensing devicehaving an adhesive dispensing orifice.
 5. The system of claim 1, thestrand orienting pin having an axial dimension substantially parallel toa direction of the fluid dispensing orifice, the strand orienting pinhaving a recessed side portion.
 6. A system for applying coatingmaterials onto a strand, the system comprising: a fluid dispensingdevice having a fluid dispensing orifice from which fluid is dispensed,a strand guide member coupled to the fluid dispensing device, the strandguide for guiding a strand drawn past fluid dispensing orifice, a strandorienting pin located between the strand guide member and the fluiddispensing orifice so that a strand drawn from the strand guide memberover the fluid dispensing orifice is engaged with the strand orientingpin, a module, a plate mounted on a bottom portion of the module andextending beyond an end portion of the module to which the fluiddispensing device is coupled, the plate having an opening aligned withthe fluid dispensing orifice.
 7. The system of claim 6, the strandorienting pin protruding from a side of the plate opposite from a sideof the plate on which the fluid dispensing device is located.
 8. Thesystem of claim 7, the strand guide member is a roller including astrand guide groove, the strand orienting pin offset relative to a pathbetween the fluid dispensing orifice and the strand guide groove.
 9. Thesystem of claim 6, the fluid dispensing device is an adhesive dispensingdevice.